From 395915dae1571e10e2766c999974de864655ea3a Mon Sep 17 00:00:00 2001 From: ikerexxe Date: Mon, 15 Jun 2020 09:52:11 +0200 Subject: [PATCH] pam_faillock: change /run/faillock/$USER permissions to 0660 Nowadays, /run/faillock/$USER files have user:root ownership and 0600 permissions. This forces the process that writes to these files to have CAP_DAC_OVERRIDE capabilites. Just by changing the permissions to 0660 the capability can be removed, which leads to a more secure system. Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1661822 --- modules/pam_faillock/faillock.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/modules/pam_faillock/faillock.c b/modules/pam_faillock/faillock.c index e492f5f9..4ea94cbe 100644 --- a/modules/pam_faillock/faillock.c +++ b/modules/pam_faillock/faillock.c @@ -76,7 +76,7 @@ open_tally (const char *dir, const char *user, uid_t uid, int create) flags |= O_CREAT; } - fd = open(path, flags, 0600); + fd = open(path, flags, 0660); free(path); @@ -88,6 +88,18 @@ open_tally (const char *dir, const char *user, uid_t uid, int create) if (st.st_uid != uid) { ignore_return(fchown(fd, uid, -1)); } + + /* + * If umask is set to 022, as will probably in most systems, then the + * group will not be able to write to the file. So, change the file + * permissions just in case. + * Note: owners of this file are user:root, so if the permissions are + * not changed the root process writing to this file will require + * CAP_DAC_OVERRIDE. + */ + if (!(st.st_mode & S_IWGRP)) { + ignore_return(fchmod(fd, 0660)); + } } }